Today's high cost of grain and protein sources have caused poultrymen to re-examine feeding programs for commercial laying hens. Methods of feeding layers are sought which will substantially lower feed costs but yet provide adequate nutrient intake for maintaining egg production, size, quality and feed efficiency.
Investigations studying the utilization of nutrients by laying hens have taken many approaches: by limiting the quantity of feed given; restricting the feeding time; or limiting the amount of energy in the diet. A 20% reduction in feed consumption by reducing the feeding time was shown in an article by Bell and Morenz, Poultry Science 52: (1973) pp 982-991. Accompanying the reduced feed consumption was reduced egg production. A 10 to 15% reduction in feed consumption without affecting egg production was described in an article by Patel and McGinnis, Poultry Science 49: (1970) page 1425, while a 6% reduction of energy intake but not amino acids, minerals or vitamins resulted in an increase in egg production as seen in a report by Snetsinger, Zimmerman and Greene, in Poultry Science 53: (1974) page 1980. A report in Poultry Science 55 page 1941, (1976) shows a restriction of feed intake to 95, 90 or 85% of the amount consumed by full-fed controls to decrease egg production with a corresponding decrease in the level of feed intake.
Other researchers have studied the level of nutrients to provide optimum levels of performance (growth or rate of lay, egg size, etc.). While such determined levels may provide optimum nutrition and performance, they do not necessarily provide optimum economic returns to the poultry producer.
For growing animals it has been found that it is desirable to feed rations of different but adequate nutritional levels associated with the changing requirement for nutrients throughout the growing period. In practice, this means feeding a ration that is slightly deficient in amino acids during an early stage of that particular section of the growing period. Later, because of the animal's changing nutritional requirements, this ration is more than adequate and the growing animal or bird compensates by growing faster during a subsequent growth and feeding period. Thus, in meeting a growing animal's needs on a practical basis a series of rations that are alternately adequate and then deficient are provided to achieve economical and efficient growth rates.
Critical factors which influence the rehabilitation and compensatory growth after a period of undernutrition are the severity of the deficiency, the duration of the deficiency and age at the onset of the period of undernutrition and the particular species involved.
The aforementioned method of feeding can only provide economic savings if the animals are growing and have a decreasing amino acid, vitamin and mineral requirement. However, this feeding method cannot be utilized by mature animals, especially laying hens because their nutritional requirements are not diminishing and any continuous restriction of dietary intake of protein, vitamins or minerals could cause detrimental effects on body weight, egg size, egg production and feed efficiency.
There is a need for an economical method of feeding laying hens to promote the formation of egg protein without substantial monitoring cost and equipment as well as any detrimental effects on rate of lay or total feed efficiency.